Sahih al-Bukhari #7541 · Oneness, Uniqueness of Allah (Tawheed)

Sahih al-BukhariAnd Ibn 'Abbas narrated
Sahih al-Bukhari · Book 97 · Oneness, Uniqueness of Allah (Tawheed)
Sahih al-Bukhari · كتاب 97 · كتاب التوحيد
Abu Sufyan bin Harb told me that Heraclius called for his translator and then asked for the letter of the Prophet (ﷺ), and the former read it (thus): "In the Name of Allah, the Most Gracious, the Merciful. (This letter is) from Muhammad bin 'Abdullah, to Heraclius. "...O people of the Scripture (Jews and Christians): Come to a word that is just between us and you that we worship none but Allah..." (V.3:)
وَقَالَ ابْنُ عَبَّاسٍ أَخْبَرَنِي أَبُو سُفْيَانَ بْنُ حَرْبٍ، أَنَّ هِرَقْلَ، دَعَا تَرْجُمَانَهُ، ثُمَّ دَعَا بِكِتَابِ النَّبِيِّ صلى الله عليه وسلم فَقَرَأَهُ ‏
"‏ بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ مِنْ مُحَمَّدٍ عَبْدِ اللَّهِ وَرَسُولِهِ إِلَى هِرَقْلَ، وَ‏{‏يَا أَهْلَ الْكِتَابِ تَعَالَوْا إِلَى كَلِمَةٍ سَوَاءٍ بَيْنَنَا وَبَيْنَكُمْ ‏}‏‏"‏ الآيَةَ‏.‏
Reference : Sahih al-Bukhari 7541In-book reference : Book 97, Hadith 166